PABPN1

引言 遗传信息的传递和表达是一切生命活动的物质基础。在真核生物中，RNA聚合酶II转录产生多种类型的RNA，尽管这些RNA在基本结构上高度相似，它们的命运却截然不同：有些RNA被顺利转运出核，而另一些则在细胞核中迅速被识别并降解。RNA能够正确地被分选到出核或降解通路，是确保遗传信息精确表达的关键环节。研究表明，出核与降解机器通过竞争结合新生RNA来完成RNA分选。目前，领域内普遍认为出核通路在RNA分选中占主导地位，只有那些未能与出核机器结合的RNA，才会被降解机器结合并清除。然而，这种出核主导的RNA分选机制可能无法有效保证异常RNA的快速清除，从而对细胞功能产生潜在影响。 2024年10月25日，中国科学院分子细胞科学卓越创新中心程红课题组与武汉大学周宇教授合作，在Molecular Cell期刊在线发表了题为 Dual modes of ZFC3H1 confers selectivity in nuclear RNA sorting 的研究论文，提出并证明了“降解-预设”的RNA 分选新模型，改变了现有的“出核-预设”的RNA分选观点。 外切体是细胞中最主要的RNA降解机器之一，几乎参与了每个RNA分子的命运调控。外切体功能的发挥依赖于接头因子，帮助其选择性降解不同类型的底物RNA。PAXT复合体（PolyA eXosome Targeting connection）是外切体的一个重要接头因子，由MTR4和锌指蛋白ZFC3H1组成核心二聚体，并动态结合polyA结合蛋白PABPN1、锌指蛋白ZC3H3和RNA结合蛋白RBM26/27等。早期研究提出， PAXT主要结合在具有3′ polyA尾的成熟RNA上，通过MTR4招募外切体来降解这些底物。由于PAXT底物RNA与功能mRNA结构完全相同，其介导的RNA分选过程尤为具有挑战性。 在本研究中，意外发现ZFC3H1在转录早期便结合在pre-RNA（RNA前体）的5′端外显子和内含子上。有趣的是， ZFC3H1在此阶段处于自我封闭的模式，阻断了MTR4与外切体的结合，因此并不启动RNA降解。这种“占位”机制可以有效地防止出核因子过早结合而引起的RNA出核紊乱。通过多组学分析，该研究全面解析了PAXT降解底物RNA的特征，包括较少的外显子，较短的长度和较长的polyA尾等。这些特征如何促使ZFC3H1从“占位”模式转换为“降解”模式呢？当RNA包含多个内含子时，剪接过程中出核因子会被招募，并向5′端传递，取代ZFC3H1；而对于少外显子的短RNA，其较长的polyA尾可有助于招募更多PAXT组分（如ZC3H3和RBM26/27），解除ZFC3H1的封闭状态，暴露MTR4，从而启动降解。 综上所述，本研究揭示了新生RNA的命运最初被预设为降解，但伴随转录和加工过程的推进，其命运可被重塑，RNA的特征决定了其最终被分选为出核或降解通路。基于这一发现，研究人员提出了以降解为中心的RNA分选机制，既确保了异常RNA的快速降解，又保证了功能性RNA的高效出核。这一工作揭示了细胞核RNA分选的基本规律，深化了对遗传信息精准传递的理解。 模式图（Credit: Molecular Cell） 参考文献 https://doi.org/10.1016/j.molcel.2024.09.032 责编|探索君 排版|探索君 来源|BioArt End 往期精选 围观 一文读透细胞死亡(Cell Death) | 24年Cell重磅综述（长文收藏版） 热文 Cell | 是什么决定了细胞的大小？ 热文 Nature | 2024年值得关注的七项技术 热文 Nature | 自身免疫性疾病能被治愈吗？科学家们终于看到了希望 热文 CRISPR技术进化史 | 24年Cell综述

▎药明康德内容团队编辑 本期看点 1. 新型IL-15受体激动剂NKTR-255联用嵌合抗原受体（CAR）-T细胞疗法治疗复发或难治性B细胞急性淋巴细胞白血病（B-ALL），患者12个月时的无进展生存率是单独使用CAR-T细胞疗法历史对照组的两倍（67%对比38%）。 2. 单抗疗法briquilimab在针对慢性诱发性荨麻疹（CIndU）患者开展的1b/2a期研究中表现亮眼，93%的患者在接受治疗后6周达成缓解。 3. 首个进入人体临床试验的工程化B细胞疗法ISP-001的初步结果积极，首位接受治疗的1型黏多糖贮积症（MPS I）患者已停止使用标准疗法。 药明康德内容团队整理 NKTR-255：公布1期联合治疗试验数据 Nektar Therapeutics公司公布了一项1期研究的首个临床数据，该研究评估了其新型IL-15受体激动剂NKTR-255联用靶向CD19和CD22的自体双特异性CAR-T细胞疗法治疗复发或难治性B细胞急性淋巴细胞白血病患者的效果。NKTR-255是一种聚合物偶联人IL-15，它能保持与IL-15受体α亚基的结合亲和力，并降低清除率，从而提供持续的药效学作用。NKTR-255具有增强免疫治疗效果的潜力。 此次公布的结果显示，NKTR-255联用CAR-T细胞疗法治疗复发或难治性B-ALL患者的疗效良好。9名患者中有8名获得了完全缓解（CR），伴有或不伴有血液学恢复，所有患者均未检测到微小残留病（MRD）。此外，与仅接受相同CAR-T细胞疗法的历史对照组相比，NKTR-255联用CAR-T细胞疗法组患者的12个月无复发生存率更高（67%对比38%）。历史对照组患者的中位无复发生存期（RFS）为3.9个月，联合治疗组患者接受随访超过14个月，中位RFS尚未达到。安全性方面，未观察到与NKTR-255相关的剂量限制性毒性。联合治疗组中观察到的毒性与单独使用CAR-T细胞治疗后观察到的毒性相似。 Briquilimab：公布1b/2a期临床试验数据 Jasper Therapeutics公司公布了其候选单抗briquilimab用于治疗慢性诱发性荨麻疹的1b/2a期研究SPOTLIGHT的初步数据。Briquilimab是一种非糖基化单克隆抗体，可通过靶向细胞表面受体c-Kit（也称为CD117）以避免与干细胞因子结合，从而阻断肥大细胞中的关键生存信号，造成细胞凋亡与耗竭，从而消除肥大细胞驱动疾病（如慢性荨麻疹）中炎症反应的潜在来源。 此次公布的结果显示，CIndU患者在接受briquilimab皮下注射后1周便观察到CR，且93%的患者在接受治疗后6周达成缓解。120毫克剂量组中，12名患者中有10名（83%）达到了CR，1名达成部分缓解（PR）。40毫克组中，1名患者达成CR，2名患者达成PR。该公司已获得监管批准在SPOTLIGHT研究中招募患者接受更高剂量药物的治疗。 ISP-001：公布1期临床试验中首例患者的数据 Immusoft公司公布了首位接受其工程化B细胞疗法ISP-001治疗的1型黏多糖贮积症患者的积极结果。根据新闻稿，ISP-001是首个进入人体临床试验的工程化B细胞疗法。该疗法使用非病毒载体将表达α-L-艾杜糖苷酶的转基因引入B细胞中，能够让经过改造的B细胞长期大量生产治疗性蛋白，从而改善患者症状。 此次公布的临床试验结果显示，首位接受ISP-001治疗的患者在接受治疗3-8个月后，尿液中的多糖疾病生物标志物水平降低到正常范围内。这名患者脑脊液中的硫酸乙酰肝素（HS）水平在接受治疗6个月时降低25%。这是FDA认可的一个与MPS I疾病活动相关的替代终点。生物标志物之外，这名患者的6分钟行走检测表现提高30%，并且肩部活动范围在6个月时得到改善。关节僵硬是MPS I的症状之一。在接受治疗8个月后，该患者停止使用标准酶替代疗法（ERT）。随后的一个月里，患者的6分钟行走检测表现仍然获得改善，不过幅度比6个月时有所下降，肩部活动范围的改善得到维持。安全性方面，ISP-001的耐受性良好。截至2024年9月19日，尚未报告任何不良事件。 WVE-006：公布1b/2a期临床试验数据 Wave Life Sciences公司公布了其在研RNA编辑候选疗法WVE-006用于治疗α-1抗胰蛋白酶缺乏症（AATD）的1b/2a期临床试验RestorAATion-2的积极结果。AATD是一种可影响肺和肝脏功能的遗传疾病，患者除了缺乏具有正常功能的α-1抗胰蛋白酶（AAT），其突变型AAT蛋白的积累也会损害肝脏和肺部。WVE-006是一款通过PN化学修饰和GalNAc偶联，以皮下注射方式给药的潜在“first-in-class”RNA编辑寡核苷酸疗法。WVE-006的设计旨在修复SERPINA1等位基因编码mRNA中的单碱基突变，从而恢复血液中的功能性野生型AAT蛋白，同时减少异常AAT蛋白的存在，以潜在治疗AATD相关的肺病和/或肝病。 此次公布的结果显示，WVE-006能够成功编辑AATD患者的基因。基线时未能检测到患者体内的AAT蛋白，而在试验第15天时，患者的平均总AAT蛋白水平达到10.8微摩尔，达到了监管机构批准AAT增强疗法的标准。此外，早在试验第3天，患者的总AAT和M-AAT蛋白水平即较基线增加，并持续到第57天。根据新闻稿，WVE-006是首个进入临床开发的RNA编辑疗法，该试验结果是RNA编辑疗法在人体当中完成的首次机制验证。 BB-301：公布1b/2a期临床试验中前两例患者的数据 Benitec Biopharma公司公布了其开发用于治疗眼咽肌营养不良（OPMD）的沉默和取代基因疗法BB-301在早期临床试验中的前两例患者的积极数据。该疗法利用一种新型的、经过改良的AAV9载体，表达一种独特的、单一的双功能构建体，从而能够促进密码子优化的PABPN1基因和两个针对PABPN1突变体siRNA的共同表达。这两个siRNA被塑造成微RNA骨架，以抑制有缺陷的PABPN1突变体的表达，同时允许表达经过密码子优化的PABPN1基因，用PABPN1蛋白的功能性版本取代突变体。 两名患者接受了最低剂量的BB-301治疗，未报告值得注意的不良事件。此次公布的结果显示，1号患者和2号患者分别在接受BB-301治疗9个月和6个月后，吞咽功能得到了持久且有临床意义的改善。其中，在基线时症状更轻的2号患者的悉尼吞咽问卷评分已达到了临床定义的正常水平。新闻稿指出，这是使用新型基因疗法成功改善OPMD患者吞咽功能的首次报道。 SR-02：IND申请获得FDA许可 Seraxis公司宣布，其新型胰岛替代疗法SR-02的IND申请已获得FDA许可，可开展1/2期临床研究。SR-02由同种异体胰腺内分泌细胞簇组成，当被植入网膜时，可在患者自身的胰腺外形成功能性内分泌胰腺。SR-02能够以临床规模生产，由健康供体胰腺组织进行重编程后产生的专有干细胞系制成。新闻稿指出，SR-02作为一种有潜力功能性治愈需要胰岛素的糖尿病患者的疗法，是FDA许可的首个可用于人体试验的重编程干细胞衍生的候选胰腺产品。 CLN-978：IND申请获得FDA许可 Cullinan Therapeutics公司宣布，美国FDA批准了其新型、高效的CD19 x CD3靶向双特异性T细胞接合器CLN-978的IND申请，其针对中度至重度系统性红斑狼疮（SLE）患者的全球1期临床试验可在美国开展。新闻稿指出，CLN-978是首个在自身免疫疾病领域获得美国FDA授予IND批准的在研CD19靶向T细胞接合器。 CLN-978可在体外和体内引发对表达CD19的靶细胞的定向裂解。CLN-978与CD19的结合亲和力极高，可有效靶向B细胞，包括CD19水平极低的B细胞。CLN-978的分子量小（65 kDa），含有两个单链可变片段，一个与CD19结合，另一个与T细胞上的CD3结合，还有一个与人血清白蛋白结合的单结构域抗体，可延长血清半衰期。CLN-978有望为SLE和类风湿性关节炎等自身免疫疾病患者提供一种方便、现货型、皮下注射的治疗选择。 ▲欲了解更多前沿技术在生物医药产业中的应用，请长按扫描上方二维码，即可访问“药明直播间”，观看相关话题的直播讨论与精彩回放 参考资料（可上下滑动查看） [1] Immusoft to Announce Positive Phase 1 Data for First Engineered B Cell Therapy in a Clinical Trial. Retrieved October 15, 2024, from https://www.prnewswire.com/news-releases/immusoft-to-announce-positive-phase-1-data-for-first-engineered-b-cell-therapy-in-a-clinical-trial-302255551.html [2] Seraxis Announces FDA IND Allowance for Clinical Study of SR-02 Replacement Islets for Type 1 Diabetes. Retrieved October 18, 2024, from https://seraxis.com/wp-content/uploads/2024/10/Seraxis-IND-clearance-PR-FINAL-for-release-15Oct2024.pdf [3] Nektar Announces Publication in Blood of Phase 1 Data for Novel IL-15 Agonist NKTR-255 in Combination with Autologous CD19-22 CAR-T Cell Therapy in Patients with B-cell Acute Lymphoblastic Leukemia. Retrieved October 18, 2024, from https://ir.nektar.com/news-releases/news-release-details/nektar-announces-publication-blood-phase-1-data-novel-il-15 [4] Jasper Therapeutics Reports Positive Data from SPOTLIGHT Study of Briquilimab in Chronic Inducible Urticaria. Retrieved October 14, 2024 from https://www.globenewswire.com/news-release/2024/10/14/2962446/0/en/Jasper-Therapeutics-Reports-Positive-Data-from-SPOTLIGHT-Study-of-Briquilimab-in-Chronic-Inducible-Urticaria.html [5] Wave Life Sciences Announces First-Ever Therapeutic RNA Editing in Humans Achieved in RestorAATion-2 Trial of WVE-006 in Alpha-1 Antitrypsin Deficiency. Retrieved October 16, 2024 from https://www.globenewswire.com/news-release/2024/10/16/2964053/0/en/Wave-Life-Sciences-Announces-First-Ever-Therapeutic-RNA-Editing-in-Humans-Achieved-in-RestorAATion-2-Trial-of-WVE-006-in-Alpha-1-Antitrypsin-Deficiency.html [6] Benitec Biopharma Reports Positive Data from Two Subjects Treated with Low-Dose BB-301 in Phase 1b/2a Study Presented at 29th Annual Congress of the World Muscle Society. Retrieved October 18, 2024, from https://www.globenewswire.com/news-release/2024/10/12/2962249/0/en/Benitec-Biopharma-Reports-Positive-Data-from-Two-Subjects-Treated-with-Low-Dose-BB-301-in-Phase-1b-2a-Study-Presented-at-29th-Annual-Congress-of-the-World-Muscle-Society.html [7] Cullinan Therapeutics Receives U.S. FDA Clearance of Investigational New Drug Application for CLN-978 Administered Subcutaneously in Patients with Moderate to Severe Systemic Lupus Erythematosus. Retrieved October 18, 2024, from https://investors.cullinantherapeutics.com/news-releases/news-release-details/cullinan-therapeutics-receives-us-fda-clearance-investigational [8] SystImmune, Inc. Announces FDA Clearance of IND Application for BL-M11D1 in Relapsed/Refractory Acute Myeloid Leukemia. Retrieved October 18, 2024, from https://www.prnewswire.com/news-releases/systimmune-inc-announces-fda-clearance-of-ind-application-for-bl-m11d1-in-relapsedrefractory-acute-myeloid-leukemia-302275098.html [9] Circle Pharma announces first patients dosed in Phase 1 clinical trial of first-in-class oral Cyclin A/B RxL inhibitor CID-078 for advanced solid tumors. Retrieved October 18, 2024, from https://circlepharma.com/circle-pharma-announces-first-patients-dosed-in-phase-1-clinical-trial-of-first-in-class-oral-cyclin-a-b-rxl-inhibitor-brcid-078-for-advanced-solid-tumors [10] Immutep Announces First-in-Human Phase I Study of IMP761 Progresses to Dose Escalation Portion of Trial. Retrieved October 18, 2024, from https://www.globenewswire.com/news-release/2024/10/17/2964816/0/en/Immutep-Announces-First-in-Human-Phase-I-Study-of-IMP761-Progresses-to-Dose-Escalation-Portion-of-Trial.html [11] Bright Peak Therapeutics Announces Dosing of First Patient in Phase 1/2a Clinical Trial of BPT567, a First-in-Class Bifunctional PD1-IL18 Immunoconjugate. Retrieved October 18, 2024, from https://brightpeaktx.com/bright-peak-therapeutics-announces-dosing-of-first-patient-in-phase-1-2a-clinical-trial-of-bpt567-a-first-in-class-bifunctional-pd1-il18-immunoconjugate/ [12] Athos Announces Positive Topline Phase 1 Data for its AI-Generated, Novel, Oral G9A Inhibitor ATH-063, Demonstrating Selective Expansion and Activation of Potent Anti-Inflammatory Regulatory T Cells. Retrieved October 18, 2024, from https://athostx.com/news-posts/athos-announces-positive-topline-phase-1-data-for-its-ai-generated-novel-oral-g9a-inhibitor-ath-063-demonstrating-selective-expansion-and-activation-of-potent-anti-inflammatory-regulatory-t-cells/ [13] Latigo Biotherapeutics Doses First Participant in Phase 1 Clinical Trial of LTG-305 for Non-Opioid Treatment of Pain. Retrieved October 18, 2024, from https://www.prnewswire.com/news-releases/latigo-biotherapeutics-doses-first-participant-in-phase-1-clinical-trial-of-ltg-305-for-non-opioid-treatment-of-pain-302276944.html [14] IgGenix Announces First Patient Dosed in Phase 1 Clinical Trial "ACCELERATE Peanut" Evaluating IGNX001 in Peanut Allergy. Retrieved October 18, 2024, from https://www.prnewswire.com/news-releases/iggenix-announces-first-patient-dosed-in-phase-1-clinical-trial-accelerate-peanut-evaluating-ignx001-in-peanut-allergy-302277256.html [15] Repare Therapeutics Doses First Patient in Phase 1 Clinical Trial of RP-3467, a Polθ ATPase Inhibitor. Retrieved October 18, 2024, from https://ir.reparerx.com/news-releases/news-release-details/repare-therapeutics-doses-first-patient-phase-1-clinical-trial-2 [16] uniQure Announces Dosing of First Patient in Phase I/II Clinical Trial of AMT-162 for the Treatment of SOD1-ALS. Retrieved October 18, 2024, from https://www.globenewswire.com/news-release/2024/10/15/2963063/0/en/uniQure-Announces-Dosing-of-First-Patient-in-Phase-I-II-Clinical-Trial-of-AMT-162-for-the-Treatment-of-SOD1-ALS.html#:~:text=LEXINGTON%2C%20Mass.%20and%20AMSTERDAM%2C%20Oct.%2015%2C%202024%20%28GLOBE,a%20rare%2C%20inherited%20and%20progressive%20motor%20neuron%20disease. 免责声明：药明康德内容团队专注介绍全球生物医药健康研究进展。本文仅作信息交流之目的，文中观点不代表药明康德立场，亦不代表药明康德支持或反对文中观点。本文也不是治疗方案推荐。如需获得治疗方案指导，请前往正规医院就诊。 版权说明：本文来自药明康德内容团队，欢迎个人转发至朋友圈，谢绝媒体或机构未经授权以任何形式转载至其他平台。转载授权请在「药明康德」微信公众号回复“转载”，获取转载须知。 分享，点赞，在看，聚焦全球生物医药健康创新

-Management plans to host an investor webcast on October 14th at 8:30 am EDT to provide an update for the BB-301 Phase 1b/2a Clinical Study, details below- -The webcast access information has been revised from the conference call information provided on October 12th- HAYWARD, Calif., Oct. 14, 2024 (GLOBE NEWSWIRE) -- Benitec Biopharma Inc. (NASDAQ: BNTC) (“Benitec” or “Company”), a clinical-stage, gene therapy-focused, biotechnology company developing novel genetic medicines based on its proprietary “Silence and Replace” DNA-directed RNA interference (“ddRNAi”) platform, today announces updated webcast information to discuss the interim clinical study data previously reported on Saturday, October 12th. Company Webcast Information: Webcast title: Interim BB-301 Phase 1b Clinical Study Update A live webcast of the interim clinical data presentation, including management and Emily Plowman, PhD, CCC-SLP, FASHA – Professor, Department of Otolaryngology – Head and Neck Surgery, The Ohio State University College of Medicine, will be held at 8:30AM EDT on Monday October 14th, 2024, and can be accessed by clicking on this link https://lifescievents.com/event/benitecbiopharma/. The event replay and corresponding slides will be placed on the News & Events tab on the Investor page of the Benitec website. About OPMDOPMD is a rare progressive muscle-wasting disease caused by a mutation in the poly(A)-binding protein nuclear 1 (PABPN1) gene, for which there is currently no effective drug therapy. The disease is characterized by swallowing difficulties (dysphagia), limb weakness and eyelid drooping (ptosis). Dysphagia worsens over time and can lead to chronic choking, regurgitation, aspiration pneumonia, and in severe cases, death. Available clinical and surgical interventions are limited in scope and effectiveness and do not address the underlying progressive muscle weakness. About BB-301BB-301 is a novel, modified AAV9 capsid expressing a unique, single bifunctional construct promoting co-expression of both codon-optimized Poly-A Binding Protein Nuclear-1 (PABPN1) and two small inhibitory RNAs (siRNAs) against mutant PABPN1. The two siRNAs are modeled into microRNA backbones to silence expression of faulty mutant PABPN1, while allowing expression of the codon-optimized PABPN1 to replace the mutant with a functional version of the protein. We believe the silence and replace mechanism of BB-301 is uniquely positioned for the treatment of OPMD by halting mutant expression while providing a functional replacement protein. About Benitec Biopharma, Inc.Benitec Biopharma Inc. (“Benitec” or the “Company”) is a clinical-stage biotechnology company focused on the advancement of novel genetic medicines with headquarters in Hayward, California. The proprietary “Silence and Replace” DNA-directed RNA interference platform combines RNA interference, or RNAi, with gene therapy to create medicines that simultaneously facilitate sustained silencing of disease-causing genes and concomitant delivery of wildtype replacement genes following a single administration of the therapeutic construct. The Company is developing Silence and Replace-based therapeutics for chronic and life-threatening human conditions including Oculopharyngeal Muscular Dystrophy (OPMD). A comprehensive overview of the Company can be found on Benitec’s website at www.benitec.com. Forward Looking StatementsExcept for the historical information set forth herein, the matters set forth in this press release include forward-looking statements, including statements regarding Benitec’s plans to develop and potentially commercialize its product candidates, the timing of completion of pre-clinical and clinical trials, the timing of the availability of data from our clinical trials, the timing and sufficiency of patient enrollment and dosing in clinical trials, the timing of expected regulatory filings, the clinical utility and potential attributes and benefits of ddRNAi and Benitec’s product candidates, the intellectual property position, and other forward-looking statements. These forward-looking statements are based on the Company’s current expectations and subject to risks and uncertainties that may cause actual results to differ materially, including unanticipated developments in and risks related to: unanticipated delays; further research and development and the results of clinical trials possibly being unsuccessful or insufficient to meet applicable regulatory standards or warrant continued development; the ability to enroll sufficient numbers of subjects in clinical trials; determinations made by the FDA and other governmental authorities; the Company’s ability to protect and enforce its patents and other intellectual property rights; the Company’s dependence on its relationships with its collaboration partners and other third parties; the efficacy or safety of the Company’s products and the products of the Company’s collaboration partners; the acceptance of the Company’s products and the products of the Company’s collaboration partners in the marketplace; market competition; sales, marketing, manufacturing and distribution requirements; greater than expected expenses; expenses relating to litigation or strategic activities; the Company’s ability to satisfy its capital needs through increasing its revenue and obtaining additional financing, given market conditions and other factors, including our capital structure; our ability to continue as a going concern; the length of time over which the Company expects its cash and cash equivalents to be sufficient to execute on its business plan; the impact of local, regional, and national and international economic conditions and events; and other risks detailed from time to time in the Company’s reports filed with the Securities and Exchange Commission. The Company disclaims any intent or obligation to update these forward-looking statements. Investor Relations Contact:Irina KofflerLifeSci Advisors, LLC(917) 734-7387ikoffler@lifesciadvisors.com